Engine lubricant compositions may be selected to provide an increased engine protection while providing reduced emissions. In order to reduce emissions, there is a trend toward lubricant compositions having a reduced ash value. However, in order to achieve benefits of reduced ash value to reduce emissions, a balance between engine protection and lubricating properties is required for the lubricant composition. For example, an increase in the amount of detergent in a lubricant composition may be beneficial for engine protection purposes but may lead to higher ash values. Likewise, an increase in the amount of ashless dispersant may be beneficial to increase engine protection, but may result in poorer seal protection performance. Accordingly, there is a need for improved lubricant compositions that are suitable for meeting or exceeding currently proposed and future lubricant performance standards.
With regard to the foregoing, embodiments of the disclosure provide an ashless additive for lubricating oil compositions, lubricating oil compositions and methods for lubricating that are effective to improve the total base number (TBN) of a lubricant composition. The additive is a reaction product of a compound of the formula:
with NH3, an alcohol, an amine, or a hydrocarbyl amine, wherein R1 is selected from H, a hydrocarbyl group. The alcohol or amine contains from 1 to about 24 carbon atoms, and the hydrocarbyl amine has a number average molecular weight ranging from about 100 to about 6000.
A further embodiment of the disclosure provides an engine lubricant composition including base oil and an ashless additive that is a reaction product of a compound of the formula:
and NH3, an alcohol or an amine or a hydrocarbyl amine, wherein the alcohol or amine contains from 1 to about 24 carbon atoms and wherein the hydrocarbyl amine has a number average molecular weight ranging from about 100 to about 6000. In the formula R1 is H, or a hydrocarbyl group.
Another embodiment of the disclosure provides a method for boosting the total base number (TBN) of a lubricant composition for an engine by from about 1 to about 50 percent over a base value of the TBN of the lubricant composition. The method includes adding to the lubricant composition a minor amount of an ashless additive compound of the formula:
wherein Y is selected from the group consisting of OR and NR2R3 wherein R is a hydrocarbyl group containing from 1 to about 24 carbon atoms, R2 and R3 are selected from H and a hydrocarbyl group.
In another embodiment there is provided a method for increasing a total base number (TBN) of a lubricant composition while maintaining seal compatibility of the lubricant composition. The method includes boosting the total base number of the lubricant composition by incorporating a minor amount of an ashless additive compound of the formula:
in the lubricant composition, wherein Y is selected from the group consisting of OR and NR2R3 wherein R is a hydrocarbyl group containing from 1 to about 24 carbon atoms, R2 and R3 are selected from H and a hydrocarbyl group and R2 and R3 may be the same or different. An advantage of the use of an additive composition according to the disclosure is that lubricant formulations containing the additive may exhibit lower sulfated ash content.
A further advantage of the additive composition described herein is that the additive may be effective to boost the TBN of the lubricant formulation with minimal amount of adverse affect on elastomeric seals compared to conventional ashless TBN providing compositions. Conventional methods for increasing the ashless TBN of a lubricant composition may include, but are not limited to, increasing the amount of dispersant in the lubricant composition. Dispersants are typically nitrogen-containing compounds with a polymeric backbone that may be incompatible with or detrimental to elastomeric seals. Further benefits and advantages may be evident from the following disclosure.
The following definitions of terms are provided in order to clarify the meanings of certain terms as used herein.
As used herein, the terms “oil composition,” “lubrication composition,” “lubricating oil composition,” “lubricating oil,” “lubricant composition,” “lubricating composition,” “fully formulated lubricant composition,” and “lubricant” are considered synonymous, fully interchangeable terminology referring to the finished lubrication product comprising a major amount of a base oil plus a minor amount of an additive composition.
As used herein, the terms “additive package,” “additive concentrate,” and “additive composition” are considered synonymous, fully interchangeable terminology referring the portion of the lubricating composition excluding the major amount of base oil stock mixture.
As used herein, the term “hydrocarbyl substituent” or “hydrocarbyl group” is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character. Examples of hydrocarbyl groups include:                (1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form an alicyclic radical);        (2) substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);        (3) hetero substituents, that is, substituents which, while having a predominantly hydrocarbon character, in the context of this invention, contain other than carbon in a ring or chain otherwise composed of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen, and encompass substituents such as pyridyl, furyl, thienyl, and imidazolyl. In general, no more than two, for example, no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; typically, there will be no non-hydrocarbon substituents in the hydrocarbyl group.        
As used herein, the term “percent by weight”, unless expressly stated otherwise, means the percentage the recited component represents to the weight of the entire composition.
The terms “oil-soluble” or “dispersible” used herein do not necessarily indicate that the compounds or additives are soluble, dissolvable, miscible, or capable of being suspended in the oil in all proportions. The foregoing terms do mean, however, that they are, for instance, soluble or stably dispersible in oil to an extent sufficient to exert their intended effect in the environment in which the oil is employed. Moreover, the additional incorporation of other additives may also permit incorporation of higher levels of a particular additive, if desired.
Engine lubricating oils of the present disclosure may be formulated by the addition of one or more additives, as described in detail below, to an appropriate base oil formulation. The additives may be combined with a base oil in the form of an additive package (or concentrate) or, alternatively, may be combined individually with a base oil. The fully formulated crankcase lubricant may exhibit improved performance properties, based on the additives added and their respective proportions.
Additional details and advantages of the disclosure will be set forth in part in the description which follows, and/or may be learned by practice of the disclosure. The details and advantages of the disclosure may be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed.